[CAMEL-17551] camel-pulsar: Pause Pulsar consumers when a Pulsar route is suspended

• Type: Improvement
• Status: Resolved
• Priority: Minor
• Resolution: Fixed
• Fix Version/s: 3.16.0
• Component/s: camel-pulsar

Environment

Camel 3.12.0, Pulsar 2.7.2

• Estimated Complexity: Unknown

Language

Java

• Assignee: Unassigned
• Reporter: Suzanne Becker
• Created: 25/Jan/22 17:17
• Updated: 03/Feb/22 06:52
• Resolved: 03/Feb/22 06:52

Description

Proposed change

When a Pulsar route is suspended/resumed, the route's PulsarConsumer should pause() and resume() its Pulsar consumers.

Background

Camel's PulsarConsumer is not currently suspendable. When `suspend()` is called on a Pulsar endpoint/route, the route and its PulsarConsumer are stopped instead, which in the current implementation will stop+close the underlying Pulsar consumers.

As a result, in-flight exchanges cannot complete because the Pulsar consumers can't ack messages when in a closed state. 

Pulsar consumers can be paused and resumed instead. A paused Pulsar consumer does not request any more messages from the broker, but it can still communicate with the broker, for example to ack messages it's already received. (However, after calling .pause() on a Pulsar consumer, it will finish processing any messages that were buffered in its receiver queue – up to `receiverQueueSize` # of messages). 

Issue Links

• links to: GitHub Pull Request #6881